Not long after a truck plowed through a busy Christmas market in Berlin killing 12 people, Twitter users who support Donald Trump began filling the social platform with anti-Merkel-messages and links to stories critical of her government's refugee policy.

It's not surprising that people who seem to support Trump would be critical of Merkel in the aftermath of the attack. But some experts are now saying that at least some of the onslaught of anti-Merkel content on Twitter came from bot accounts and trolls that are shifting from bolstering Donald Trump to trying to tear down the German leader as she prepares to run for re-election in 2017.

For example, a popular Angela Merkel parody Twitter account was bombarded with messages that called the German chancellor a "mass murderer" who is "exterminating the German people."

In both cases, the parody accounts pointed the finger at Russia, which runs a well-documented online disinformation operation that employs real people to run Twitter accounts that help create and spread messages that fit with the Kremlin line and objectives. The operation also uses automated Twitter accounts, known as bots, to help further amplify messages on Twitter.

The CIA and FBI now agree that Russia tried to interfere in the US election to benefit Trump, and online efforts were a part of it. (The agencies have not released their findings to the public.)

Experts in Kremlin propaganda and online misinformation in Germany say Russia is already stepping up efforts in Germany.

Simon Hegelich, a political scientist at Munich’s Technical University, told Bloomberg his research found that trolls and bots are already shifting their attention to Germany.

“There’s a lot of evidence that there are now targeted attempts to massively attack Merkel, including with bots,” he said. “A lot of accounts that pretty obviously are pro-Trump bots are now joining the anti-Merkel debate.”

Jakub Janda leads the Kremlin Watch program at the European Values think-tank that collects and analyzes examples of Russian disinformation in Europe and elsewhere. He recently wrote that "Merkel will be the next target of full-scale disinformation and influence operations of the Kremlin and its proxies."

Janda told BuzzFeed News he doesn't think anti-Merkel trolling in English will have much effect on Germans in the election. But he said "it needs to be followed and I think Twitter needs to do much more with this."

Janda said he expects new online media outlets to launch next year in Germany and to begin pumping out anti-Merkel content and even fake news.

"For the assault on Merkel, most of it would make sense to be happening in the German language and in smaller German outlets," he said.

In fact, fake news about immigrants is already starting to spread in Germany.

"Earlier this year, Russian media and pro-Russian trolls helped to create online hysteria by promoting a fake story of a Russian girl allegedly raped by a Syrian immigrant," wrote Anne Applebaum, a foreign affairs columnist for The Washington Post.

Craig Silverman is a media editor for BuzzFeed News and is based in Toronto.